Smart neurons: Single neuronal dendrites can perform computations

Smart neurons: Single neuronal dendrites can perform computations

When you look at the hands of a clock or the streets on a map, your brain is effortlessly performing computations that tell you about the orientation of these objects. New research by UCL scientists has shown that these computations can be carried out by the microscopic branches of neurons known as dendrites, which are the receiving elements of neurons.

The study, published today (Sunday) in Nature and carried out by researchers based at the Wolfson Institute for Biomedical Research at UCL, the MRC Laboratory for Molecular Biology in Cambridge and the University of North Carolina at Chapel Hill, examined neurons in areas of the mouse brain which are responsible for processing visual input from the eyes. The scientists achieved an important breakthrough: they succeeded in making incredibly challenging electrical and optical recordings directly from the tiny dendrites of neurons in the intact brain while the brain was processing visual information.

These recordings revealed that visual stimulation produces specific electrical signals in the dendrites – bursts of spikes – which are tuned to the properties of the visual stimulus.

The results challenge the widely held view that this kind of computation is achieved only by large numbers of neurons working together, and demonstrate how the basic components of the brain are exceptionally powerful computing devices in their own right.

If this is confirmed and confirmed across species, we will have to reexamine what we think we know about the “complexity” of the “lower” (no such thing) animals.

Totally exposing my ignorance here, but I have long marveled at (and wondered about) the way that supposedly “simple” creatures such as insects perform seemingly sophisticated tasks. I’ve always heard that insects act purely “on instinct”, but I never get a particularly good explanation of how this “instinct” is stored or transmitted. Could this be part of it? Perhaps it doesn’t take a large mass of neurons after all to process information and react accordingly?

If this is confirmed and confirmed across species, we will have to reexamine what we think we know about the “complexity” of the “lower” (no such thing) animals.

Totally exposing my ignorance here, but I have long marveled at (and wondered about) the way that suppos…

Apologies is this is a bit of a mindfuck, but look at hyperNEAT. A genetic algorithm controls the growth of an artificial neural network which works as soon as it is created. I have seen art created by hyperNEAT (the value of the weights in the ANN are displayed as pixels), but can’t find them any more.

Perhaps it doesn’t take a large mass of neurons after all to process information and react accordingly?

Furthermore, this could tie in with new research on Artificial Life and autonomous agents. I love that branch of computing, where emergent behavior is basically ‘grown’ out of simple evolutionary principles, feedback and past experiences. But it’s still mostly software, and based on neural networks, whereas this suggests the neuron themselves are more involved in the process and not just logical / neuro-fuzzy networks. Probably nothing new for the specialists, but still.

Many animals have responses that are conditioned to certain specific stimuli. There are fixed action patters (awesome stuff, too much to list here, but google it). Also, there are seemingly complex behaviors that are actually governed by a very small subset of “commands”. For example, the behavior of fish in a school where they all appear to shift simultaneously has one rule. Don’t let anyone closer than a foot. It manifests in some really cool behavior. Look at a flock of birds tearing across the sky and they all break one way or another … or a bait ball…

Look up the different types of learning (FAP’s, habituation, associative, imprinting, and the “higher cognitive learning types”…) really awesome stuff…

@OP – The scientists achieved an important breakthrough: they succeeded in making incredibly challenging electrical and optical recordings directly from the tiny dendrites of neurons in the intact brain while the brain was processing visual information.

This may help to build on to this project covering the bigger picture:

This does not surprise me very much because the last 50 years have seen progressively more discoveries of added complexity in specific individual neurons. Yes, there are some simple one that do little more than relay activation spikes, but when you look at cells that have dendrite trees with the order of 10,000 impinging synapses, you naturally expect something very complex is going on. These large cells have a great potential for big internal state phase space. If you look at the chemical pathways map for any eukaryotic cell, it’s huge. Add to that all the chemical pathways that neurons use for processing of neurotransmitter chemicals, and it really is boggling.

Early numeric information processing by humans was sometimes done by putting or taking small stones from pouches. Cells are pouches of molecules that can hold and process information represented by the presence and numerical weighting of a vast selection of possible molecules. That takes less energy and space to do the same work as a network of the kinds of simple gates that were used as models for neurons half a century ago. What keeps popping up is Orgel’s Second Rule: Evolution is cleverer than you are.

It wouldn’t surprise me. There are animals which exhibit complex looking behaviour with relatively few neurons.For example – the portia spider.
On the other hand I wouldn’t read anything into any neurological result until a follow-up is published,